Glad to see crystal set radio is still alive and well. As a young boy in the 50's with ex-WD earphones, the magic crystal and wires, we could listen to the World.
I was just buying magnet wire on amazon, and it suggested a crystal radio piezoelectric earpiece. I couldn’t quite remember where I saw it before. But now I remember I had one of those 100 in 1 circuit discovery sets when I was 5, and it had components to build a crystal radio. I remember being disappointed though, because it didn’t pick up FM. Only sports, talk radio, and classical music. And I eventually blew out the earpiece by hooking direct voltage to it to out of curiosity.
Curiosity and experimentation are essential in learning - we all blew things up when we were experimenting. However, I can remember having a crystal microphone. It was cheap and plastic and the only way in to see what was inside was to remove the thin tin foil diaphragm, which I did. I think I replaced it with a foil milk bottle top. It still worked (surprisingly) but I dread to think what the quality was like! . . . but it was good to find out what was inside.
We will try to keep up the same standards - We are currently working on a lot more videos to appear over the coming weeks and months. Thanks for your comment.
I’m glad you liked the video. In terms off the length, generally as long as you can make it. Possibly 50ft (27metres or so) but this isn’t exact. It really depends what you can do because the length would ideally be about a quarter wavelength long, but this is not feasible for most people.
You can also use any powered speaker with a 3.5mm jack. If you solder it to the speaker connection, you will be able to hear the radio channels. Just ensure that the speaker is connected to a power source.
Yes, that is a great idea and one that’s very easy for. Some Bluetooth speakers can be bought for very little and they normally have an analogue input. Great thinking.
Thanks for your comment. We are in the process of producing a number of further videos, so we hope that you will be able to learn from these new ones as well.
That is the "ground" connection. The antenna is a wire up in the air. They go to opposite ends of the coil. Radio signals appear as a voltage difference between the antenna and ground. To get good operation, you need both connections.
Nothing but obvious or brainless easy to understand topics were talked about. this video sucks and I was expecting to finally figure this out so I can get my radio working but I didn’t learn nothing 👎🏻
There is. There are companies that use cell phone towers for wireless internet to rural places. Then you have Hughes Net, which uses satellite technology. Even ham radio operators use Winlink for sending e-mails via their radios and computers.
Greetings Mr Poole, I have an interesting question that you might be able to answer about a crystal radio. In the early 1990's , I purchased a 100 in 1 electronics kit. I followed the wiring instructions to make this project work. I could here AM radio transmission,eve when I removed the battery. The radio station I was listening to,was located in a city one hour away from where I live. The city I live had quite a few AM stations. Perhaps the frequency of the distant station was stronger? If any enthusiasts of crystal radios have a better explanations,or would like more information, I will be pleased to reply, thank you.
Without directly looking at your radio, my guess is that you were receiving a very strong signal froth e station in question. When you removed the battery, it will still strong enough to be detected or demodulated by the diode detector and to give audio in the output device. Really an unpowered crystal set - the original crystal set radios did not use a battery or have any amplifiers. I myself experienced a similar effect many years ago. Radio Moscow was broadcasting to the UK or Europe and had a very strong signal. It was so strong that the signal was picked up on the loudspeaker leads of my Hi-Fi system and rectified by the output devices in my amplifier and I could then hear the signal even with the system turned off. It just shows what can happen.
@@ElectronicsNotes Thank you Mr Poole for your well informed reply Perhap more information might be more helpful. The crystal radio was a project in the 100 in 1 electronics kit. The radio station was called 3GL on the AM dial. The city is called Geelong which is about 89 KM from where I live as I am in a suburb of the city of Melbourne. Australia.Melbourne has more radio stations,and somehow this radio project captured the radio station in Geelong. Perhaps radio 3GL had a stronger frequency. From what I know 3GL is now an FM radio station like many radio stations are going to the FM dial and even DAB. The question I ask myself is as technology is changing rapidly, will we still be able to hear radio frequencies on crystal radios or perhaps create FM crystal radios?
@@julians9070 It could be any one of a number of reasons why you are receiving that station - may be you have a wire that is resonant on the frequency of that station, etc . . . . As for the move to FM - you will need a proper FM radio for that. Crystal sets will really only receive AM stations because they detect the amplitude variations, and the tuned circuits are very broad and will not allow normal FM to be detected properly. The concept of a crystal radio is that they use a diode detector that enables amplitude variations to be detected, so unfortunately FM is not viable for them.
@@ElectronicsNotes Thank you Mr Poole for your knowledgeable reply. As the crystal radio was one of many projects on the 100 in 1 electronics kit, you may be correct in saying that I had a wire that was resonant on the frequency of that station. If I work on another type of crystal radio in future, not using the 100 in 1 electronics kit, I can imagine which AM station I pick up. I sometimes wonder which radio station and what frequency a person could hear depending on their location, on the crystal radio toy that came with the six million dollar man super hero doll? You have encouraged me to delve deeper in appreciating crystal radios. Perhaps you may have heard about the Tesla sprit radio?. Kind regards.
You could use an amplifier on the output if the crystal set, but it is likely for most op amps that the incoming frequencies are too high to get much amplification out. If you wanted to add RF amplification then a transistor or FET might be the answer.
The coil is part of the trend circuit - it resonates with the variable capacitor and provides the selectivity so that only stations not he required frequency are heard.
But why does the crystal have to be there to rectify the signal? Or, IOW, why bother transmitting both sidebands if the receiver is only going to lop off half of it? The headphone requires a push-pull effect to drive the voice coil/diaphragm? You can't get that from just the upper half only? As you can see, IDK what I am talking about. Please help. :)
In the day when crystal sets were used the technology to transmit single sideband was not available. Also both side bands are used when using a crystal diode envelope detector. Hope that helps.
@@ElectronicsNotes OK, now I see! I never realized the AM signal was the same above-and-below the line. If we sent both sides to the earpiece they would cancel and produce no output. So rectify it and we get a useful signal. Thanks!
The crystal is actually a diode - it was one of the earliest forms of diode. Interestingly H J Round when he was experimenting with crystal diodes discovered that he could get some types to emit light - this was the earliest indication of LEDs. If you want to use a diode today, you can replicate an early cat's whisker, or just use a current diode. Point contact or germanium are best.
ElectronicsNotes on a tangent, think it's interesting that people hate new agers for loving crystals. But the harsh reality is the entire modern computing society relies on these semiconductor crystals to create time and to build computers. They are literally full of Crystals!!! 😂😂😂😂 To me they literally a magical things.
One of the big issues with crystal radio sets is that they need a large antenna and strong stations that are relatively close by. Sadly with AM declining, it is not always easy to hear anything on crystal radio sets. Also the wiring on the radio was not entirely clear I seem to remember, but it is quite some while since I looked at it.
That’s an interesting idea. I’ve not heard that one before, but he certainly did a lot of things, many of which were way ahead of his time, and others were a bit strange.
Girls THIS IS NOT how a detector works, this video is WRONG. AM signals DO NOT have some "envelope" that "varies in strength." An AM RF signal consists of an RF carrier, often incorrectly called "dead key" by CBers. This is an UNMODULATED RF SIGNAL. When you modulate an RF carrier with AM, AKA lets say with a 1000hz audio test tone, you are, in the transmitter, RF MIXING the audio frequency signal with the RF carrier, and this CREATES the output signal, consisting of THE RF CARRIER, plus a SIDEBAND 1000Hz above the rf carrier, plus a SIDEBAND below the RF carrier by 1000 HZ. WANT PROOF? Review what is known as "sideband," or "single sideband" correctly formerly known as "single sideband suppressed carrier", in which, in the SSB transmitter, a low level AM signal is created, after which one sideband and the carrier is supressed, LEAVING ONE SIDEBAND In the receiver, the detector REVERSES the process of the transmitter modulator. The incoming signal, the two sidebands, and the carrier, MIX in the diode and produce the carrier, both sidebands, and the DIFFERENCE frequency between either and both sidebands and the carrier, leaving the audio. The RF carrier and the 2X sidebands are filtered out, bypassed, leaving ONLY the audio frequency carrier.
There are two ways of looking at an RF signal - one is on the time domain as you see on an oscilloscope, and the other is in the frequency domain as you would se on a spectrum analyser - both are equally valid depending upon what you want to see. Accordingly it is not incorrect to look at a modulated carrier in terms of an envelope - just look at it on an oscilloscope -or is this incorrect? I agree that when you look at a signal in the frequency domain you see the sidebands as you mention, but it is equally valid to look at the envelope of an amplitude modulated signal and also see how the varies in amplitude - hence the named also the power limits that are defined for signals are often defined in terms of peak envelope power - yes this is used for SSB, but it is equally also used for AM. Accordingly my explanation of demodulation in the time domain is perfectly acceptable and valid.
"Next the high frequency is filtered out." What, does the Frequency Fairy come down and wave her wand? You need to EXPLAIN how that's done. I'm left wondering how the F* that happens, dude.
Good point. The high frequency signal is filtered out by a small capacitor normally across the output of the detector diode, i.e. across the headphones. This must be small so that it does not reduce the audio. In many cases it was not required because the headphones could not respond to these high frequencies and in effect, this filtered out the signal frequency remaining on the output. Sorry for the confusion.
@@ElectronicsNotes Glad to see someone mention this "missing" capacitor. While the radio will work as presented, I learned about using this capacitor to enhance my builds around 1960.
Glad to see crystal set radio is still alive and well. As a young boy in the 50's with ex-WD earphones, the magic crystal and wires, we could listen to the World.
It certainly brings back memories - some of the first radios I built were crystal sets. That is why I became an electronics engineer.
I was just buying magnet wire on amazon, and it suggested a crystal radio piezoelectric earpiece. I couldn’t quite remember where I saw it before. But now I remember I had one of those 100 in 1 circuit discovery sets when I was 5, and it had components to build a crystal radio. I remember being disappointed though, because it didn’t pick up FM. Only sports, talk radio, and classical music. And I eventually blew out the earpiece by hooking direct voltage to it to out of curiosity.
Curiosity and experimentation are essential in learning - we all blew things up when we were experimenting. However, I can remember having a crystal microphone. It was cheap and plastic and the only way in to see what was inside was to remove the thin tin foil diaphragm, which I did. I think I replaced it with a foil milk bottle top. It still worked (surprisingly) but I dread to think what the quality was like! . . . but it was good to find out what was inside.
Elenco electronic playground 130.
Impressive you managed to detonate one of those piezoelectric earphones. Did you hook it up to mains or something?
@@qwertykeyboard5901 👀💦
We need more videos like these man! Keep up the good work. :)
We will try to keep up the same standards - We are currently working on a lot more videos to appear over the coming weeks and months. Thanks for your comment.
Thank you for your good video.
Question: 3:24 How much should be the length of the antenna ?
I’m glad you liked the video. In terms off the length, generally as long as you can make it. Possibly 50ft (27metres or so) but this isn’t exact. It really depends what you can do because the length would ideally be about a quarter wavelength long, but this is not feasible for most people.
Thank you for your explanation.
You can also use any powered speaker with a 3.5mm jack. If you solder it to the speaker connection, you will be able to hear the radio channels. Just ensure that the speaker is connected to a power source.
Yes, that is a great idea and one that’s very easy for. Some Bluetooth speakers can be bought for very little and they normally have an analogue input. Great thinking.
Tanks for your videos. They are really informative and well done. Keep up the good work.
Thanks for your comment. We are in the process of producing a number of further videos, so we hope that you will be able to learn from these new ones as well.
THIS INCORRECT explanation of detection WENT OUT in the 20's and perhaps sometime in the early 30's
See my reply below please.
Thanks
Really glad you enjoyed the video.
I had a rocket shaped one back in the day. Clipped a wire, with an alligator clip to a gas pipe and had power. Listened throughout the night.
Yes, whatever the type they were really easy to use . . and no battery needed!
Thank you for your good video.
2:44 where is the tank circuit and is the signal inverted or non inverted across the tank circuit ?
Antenna: hook up to your cold water tap, if it's electrically conductable. You will get a good range of AM stations.
That is the "ground" connection. The antenna is a wire up in the air. They go to opposite ends of the coil.
Radio signals appear as a voltage difference between the antenna and ground. To get good operation, you need both connections.
A hundred vids on youtube for xtal radio. This the only one to explain the operation thoroughly. ......
Good Job
Thanks very much for your comment.
Nothing but obvious or brainless easy to understand topics were talked about. this video sucks and I was expecting to finally figure this out so I can get my radio working but I didn’t learn nothing 👎🏻
0:58
Is the signal across the tank circuit inverted or non inverted ?
I mean: Is the input signal of the diode inverted or not inverted ?
There has GOT to be a way to receive and transmit wireless internet
Yeah we need it that's why I'm here after all this internet censorship
There is. There are companies that use cell phone towers for wireless internet to rural places. Then you have Hughes Net, which uses satellite technology. Even ham radio operators use Winlink for sending e-mails via their radios and computers.
I wouldn’t doubt they’re the key to time travel
Did you not type this on a cell phone?
Prior to receivers there will have been transmitters.
Indeed method of generating a signal is also needed.
Great video...👍
Thank you for your comment.
@@ElectronicsNotes>>> You're Welcome.
Greetings Mr Poole, I have an interesting question that you might be able to answer about a crystal radio. In the early 1990's , I purchased a 100 in 1 electronics kit. I followed the wiring instructions to make this project work. I could here AM radio transmission,eve when I removed the battery. The radio station I was listening to,was located in a city one hour away from where I live. The city I live had quite a few AM stations. Perhaps the frequency of the distant station was stronger? If any enthusiasts of crystal radios have a better explanations,or would like more information, I will be pleased to reply, thank you.
Without directly looking at your radio, my guess is that you were receiving a very strong signal froth e station in question. When you removed the battery, it will still strong enough to be detected or demodulated by the diode detector and to give audio in the output device. Really an unpowered crystal set - the original crystal set radios did not use a battery or have any amplifiers. I myself experienced a similar effect many years ago. Radio Moscow was broadcasting to the UK or Europe and had a very strong signal. It was so strong that the signal was picked up on the loudspeaker leads of my Hi-Fi system and rectified by the output devices in my amplifier and I could then hear the signal even with the system turned off. It just shows what can happen.
@@ElectronicsNotes Thank you Mr Poole for your well informed reply Perhap more information might be more helpful. The crystal radio was a project in the 100 in 1 electronics kit. The radio station was called 3GL on the AM dial. The city is called Geelong which is about 89 KM from where I live as I am in a suburb of the city of Melbourne. Australia.Melbourne has more radio stations,and somehow this radio project captured the radio station in Geelong. Perhaps radio 3GL had a stronger frequency. From what I know 3GL is now an FM radio station like many radio stations are going to the FM dial and even DAB. The question I ask myself is as technology is changing rapidly, will we still be able to hear radio frequencies on crystal radios or perhaps create FM crystal radios?
@@julians9070 It could be any one of a number of reasons why you are receiving that station - may be you have a wire that is resonant on the frequency of that station, etc . . . . As for the move to FM - you will need a proper FM radio for that. Crystal sets will really only receive AM stations because they detect the amplitude variations, and the tuned circuits are very broad and will not allow normal FM to be detected properly. The concept of a crystal radio is that they use a diode detector that enables amplitude variations to be detected, so unfortunately FM is not viable for them.
@@ElectronicsNotes Thank you Mr Poole for your knowledgeable reply. As the crystal radio was one of many projects on the 100 in 1 electronics kit, you may be correct in saying that I had a wire that was resonant on the frequency of that station. If I work on another type of crystal radio in future, not using the 100 in 1 electronics kit, I can imagine which AM station I pick up. I sometimes wonder which radio station and what frequency a person could hear depending on their location, on the crystal radio toy that came with the six million dollar man super hero doll? You have encouraged me to delve deeper in appreciating crystal radios. Perhaps you may have heard about the Tesla sprit radio?. Kind regards.
Could you use an OP-Amp to Amplify the signal coming from the antenna to the circuit, thus creating a more powerful signal?
You could use an amplifier on the output if the crystal set, but it is likely for most op amps that the incoming frequencies are too high to get much amplification out. If you wanted to add RF amplification then a transistor or FET might be the answer.
What does the coil do? I'm confused
The coil is part of the trend circuit - it resonates with the variable capacitor and provides the selectivity so that only stations not he required frequency are heard.
But why does the crystal have to be there to rectify the signal? Or, IOW, why bother transmitting both sidebands if the receiver is only going to lop off half of it?
The headphone requires a push-pull effect to drive the voice coil/diaphragm? You can't get that from just the upper half only?
As you can see, IDK what I am talking about. Please help.
:)
In the day when crystal sets were used the technology to transmit single sideband was not available. Also both side bands are used when using a crystal diode envelope detector.
Hope that helps.
@@ElectronicsNotes OK, now I see! I never realized the AM signal was the same above-and-below the line. If we sent both sides to the earpiece they would cancel and produce no output.
So rectify it and we get a useful signal.
Thanks!
thanks for the vid. one might put in a ground( earth as u all call it down there ) switch to a ground ( earth ) rod. .
Yes, a good earth or ground always helps.
Seen people do it in city apartments on 5th floor and hook to the buildings plumbing
Where do I find this kit at? This one looks hard to find.
It was on Amazon UK. I am not sure if they are available anywhere else. Often there are crystal radio sets on Amazon.
How does a crystal emulate a diode ?
The crystal is actually a diode - it was one of the earliest forms of diode. Interestingly H J Round when he was experimenting with crystal diodes discovered that he could get some types to emit light - this was the earliest indication of LEDs.
If you want to use a diode today, you can replicate an early cat's whisker, or just use a current diode. Point contact or germanium are best.
ElectronicsNotes on a tangent, think it's interesting that people hate new agers for loving crystals. But the harsh reality is the entire modern computing society relies on these semiconductor crystals to create time and to build computers. They are literally full of Crystals!!! 😂😂😂😂
To me they literally a magical things.
Indeed - silicon is a truly remarkable material.
The Ranveer show interview sent me here.
Thank you
I am glad you found it useful.
l have one in mint condition still in original box
That sounds great.
Fm Crystal radio can be made works
Unlikely to get FM to work on a crystal set as there is insufficient selectivity to get the frequency variations to give any audio output.
Purpose of capacitor?
The purpose of the capacitor is to smooth out the rectified signal. It can easily be missed off with little degradation in performance.
Second grade stuff, but I still find myself experimenting with them.
They aren’t quite at the forefront of technology (!) but as you say, they are still interesting.
I have this radio but doen'nt work as says the follower It s a S...
One of the big issues with crystal radio sets is that they need a large antenna and strong stations that are relatively close by. Sadly with AM declining, it is not always easy to hear anything on crystal radio sets.
Also the wiring on the radio was not entirely clear I seem to remember, but it is quite some while since I looked at it.
No batteries?
No batteries as the crystal set was powered purely by the power picked up in the antenna or aerial.
Generation beta will grow up and I can guarantee some of them will build a crystal radio.
A crystal radio set is a good learning exercise, although with fewer medium wave band broadcast stations, they may not be viable for much longer.
Thanks.
Didnt nikola tesla make a crystal radio to communicate with ghosts from the spirit world
That’s an interesting idea. I’ve not heard that one before, but he certainly did a lot of things, many of which were way ahead of his time, and others were a bit strange.
You might be interested in this article: www.mentalfloss.com/article/602456/thomas-edison-nikola-tesla-spirit-phone
Girls THIS IS NOT how a detector works, this video is WRONG. AM signals DO NOT have some "envelope" that "varies in strength." An AM RF signal consists of an RF carrier, often incorrectly called "dead key" by CBers. This is an UNMODULATED RF SIGNAL. When you modulate an RF carrier with AM, AKA lets say with a 1000hz audio test tone, you are, in the transmitter, RF MIXING the audio frequency signal with the RF carrier, and this CREATES the output signal, consisting of THE RF CARRIER, plus a SIDEBAND 1000Hz above the rf carrier, plus a SIDEBAND below the RF carrier by 1000 HZ. WANT PROOF? Review what is known as "sideband," or "single sideband" correctly formerly known as "single sideband suppressed carrier", in which, in the SSB transmitter, a low level AM signal is created, after which one sideband and the carrier is supressed, LEAVING ONE SIDEBAND
In the receiver, the detector REVERSES the process of the transmitter modulator. The incoming signal, the two sidebands, and the carrier, MIX in the diode and produce the carrier, both sidebands, and the DIFFERENCE frequency between either and both sidebands and the carrier, leaving the audio. The RF carrier and the 2X sidebands are filtered out, bypassed, leaving ONLY the audio frequency carrier.
There are two ways of looking at an RF signal - one is on the time domain as you see on an oscilloscope, and the other is in the frequency domain as you would se on a spectrum analyser - both are equally valid depending upon what you want to see.
Accordingly it is not incorrect to look at a modulated carrier in terms of an envelope - just look at it on an oscilloscope -or is this incorrect?
I agree that when you look at a signal in the frequency domain you see the sidebands as you mention, but it is equally valid to look at the envelope of an amplitude modulated signal and also see how the varies in amplitude - hence the named also the power limits that are defined for signals are often defined in terms of peak envelope power - yes this is used for SSB, but it is equally also used for AM.
Accordingly my explanation of demodulation in the time domain is perfectly acceptable and valid.
"Next the high frequency is filtered out."
What, does the Frequency Fairy come down and wave her wand?
You need to EXPLAIN how that's done. I'm left wondering how the F* that happens, dude.
Good point. The high frequency signal is filtered out by a small capacitor normally across the output of the detector diode, i.e. across the headphones. This must be small so that it does not reduce the audio. In many cases it was not required because the headphones could not respond to these high frequencies and in effect, this filtered out the signal frequency remaining on the output. Sorry for the confusion.
@@ElectronicsNotes Glad to see someone mention this "missing" capacitor. While the radio will work as presented, I learned about using this capacitor to enhance my builds around 1960.